Knee Injuries

Question 1

Ruptured anterior cruciate ligament

Answer 1

Sport injury
Mechanism: high twisting force applied to a bent knee
Typically presents with: loud crack, pain and RAPID joint swelling (haemoarthrosis)
Poor healing
Management: intense physiotherapy or surgery

Question 2

Ruptured posterior cruciate ligament

Answer 2

Mechanism: hyperextension injuries
Tibia lies back on the femur
Paradoxical anterior draw test

Question 3

Rupture of medial collateral ligament

Answer 3

Mechanism: leg forced into valgus via force outside the leg

Knee unstable when put into valgus position

Question 4

Menisceal tear

Answer 4

Rotational sporting injuries
Delayed knee swelling
Joint locking (Patient may develop skills to “unlock” the knee
Recurrent episodes of pain and effusions are common, often following minor trauma

Question 5

Chondromalacia patellae

Answer 5

Teenage girls, following an injury to knee e.g. Dislocation patella
Typical history of pain on going downstairs or at rest
Tenderness, quadriceps wasting

Question 6

Dislocation of the patella

Answer 6

Most commonly occurs as a traumatic primary event, either through direct trauma or through severe contraction of quadriceps with knee stretched in valgus and external rotation
Genu valgum, tibial torsion and high riding patella are risk factors
Skyline x-ray views of patella are required, although displaced patella may be clinically obvious
An osteochondral fracture is present in 5%
The condition has a 20% recurrence rate

Question 7

Fractured patella

Answer 7

2 types:

i. Direct blow to patella causing undisplaced fragments
ii. Avulsion fracture

Question 8

Tibial plateau fracture

Answer 8

Occur in the elderly (or following significant trauma in young)
Mechanism: knee forced into valgus or varus, but the knee fractures before the ligaments rupture
Varus injury affects medial plateau and if valgus injury, lateral plateau depressed fracture occurs
Classified using the Schatzker system